The aim of this research is to develop experiments and theory of helix-coil transition in nucleoprotein. The theory and experiments together will provide a powerful tool for the study of protein-DNA interaction. This will help us understand the roles of chromosonal proteins in the processes of differentiation, aging and transformation of normal cells to cancer cells. We plan to use polylysine and polyarginine of varied chain lengths, protamine and, histones and DNA of varied G C contents. Thermal denaturation, renaturation and effect of ionic strength on melting of these protein-DNA complexes and enthalpies of base pairs in protein- bound regions of the complexes will be studied. Circular dichroism will also be used for studying conformational changes of nucleoproteins before and during helix-coil transition.